Chronological time is irrelevant in story. Rend is either dead before Before Benji arrives, he could die at the same time Benji shows, or he could survive until after Benji arrives. These can all take a matter of seconds, minutes, hours, even days so long as it makes sense. 

I would suggest that if the plan is to have Rend die, that he does so before Benji arrives since that gives any last enigma or spite or anything to a PC instead of the GM. Likewise, it would be a good idea to have the final message given to someone who isn't crazy and already stuffed full of secrets. This, of course, would be a GM post and not need for the GM/PC to arrive on the scene.